1. Technical Field
The present invention relates to a method of manufacturing a piezoelectric element configured of a lower electrode, a piezoelectric layer and an upper electrode, and to a method of manufacturing a liquid-jet head including the piezoelectric element.
2. Related Art
Ink-jet recording heads with the following configuration have been put into practical use. In accordance with the configuration, parts respectively of pressure generating chambers are constructed of a vibration plate. The pressure generating chambers communicate respectively with nozzle orifices from which to eject ink droplets. This vibration plate is distorted by piezoelectric elements, and thus ink in each of the pressure generating chambers is pressurized. Thereby, ink droplets are ejected from the nozzle orifices. For example, an ink-jet recording head including piezoelectric elements formed in the following manner has been among the aforementioned type of ink-jet recording heads. In the case of this ink-jet recording head, an even layer made of a piezoelectric material is formed on an entire surface of the vibration plate by means of a film-forming technique. Subsequently, this layer made of the piezoelectric material is cut into shapes corresponding to the pressure generating chambers by the lithography method. Thus, the piezoelectric elements are formed respectively for the pressure generating chambers in a way that the piezoelectric elements are independent of one another.
In addition, piezoelectric elements which make it possible to obtain satisfactory piezoelectric properties by controlling crystal orientation of the piezoelectric layer in the following manner have been proposed as the aforementioned piezoelectric elements (see the scope of clams, the like and FIG. 6 of JP-A-11-191646). In the case of piezoelectric elements of this type, crystal orientation of the piezoelectric layer is controlled by forming a titanium layer, in an island shape, on a surface of the lower electrode, which is closer to the piezoelectric layer. The titanium layer serves as cores of crystals of this piezoelectric layer.
Indeed, JP-A-11-191646 has described that it suffices that the titanium layer is formed on the surface of the lower electrode, which is closer to the piezoelectric layer. However, JP-A-11-191646 has not defined what surface physical properties the titanium layer should desirably have.
If the surface physical properties of the lower electrode are poor, an MOD solution is applied unevenly while the piezoelectric layer is being formed on the lower electrode by means of an MOD method. Accordingly, this brings about a problem that piezoelectric elements exhibiting poor piezoelectric properties are formed.